| Description |
Following in the footsteps of ISO, recent observations with Spitzerhave revealed a population of galaxy systems which emit a huge amountof luminosity in their pure rotational mid-IR molecular hydrogenlines, in some cases reaching 10-30 percent of the bolometricluminosity. These large line-luminosities are believed to be poweredby galactic-scale shocks, which efficiently transfer kinetic energy tosmaller dense clouds in the turbulent post-shock medium. However,nothing at all is known about the other important cooling channels forthe shocked gas, such as OI, H2O, OH, and CO, some of which canrival H2 as a coolant. We propose deep PACS and SPIRE spectroscopy ofthe Giant Shock in Stephan.s Quintet and the Taffy Galaxy bridge toquantify the most important cooling channels and determine thephysical state of the gas being shocked. The results have implicationsfor understanding the importance of molecular cooling at higherredshift where turbulence and shock-heating may play a role in galaxyformation. |
